Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/10/18
Area Forecast Discussion
National Weather Service Caribou ME
956 PM EDT Mon Jul 9 2018
.SYNOPSIS...
A cold front will approach the region from Quebec tonight. The
front will cross northern areas Tuesday morning and Downeast
areas during the afternoon and evening. High pressure will
build across the region later Tuesday night into Thursday.
&&
.NEAR TERM /THROUGH TUESDAY/...
945 PM Update: Based on latest radar ref and sat imagery trends
showing a little further swrd xtnt of shwrs and cld cvr late
this eve then in our prev fcst, we updated both cld cvr and and
isold-sct shwrs/isold tstms to advc each further S ovrngt to
affect the Nrn third of the FA rather then just the xtrm NW
which is being backed up by latest hrly HRRR model sim radar ref
runs. Fcst 6 hrly QPFs were adjusted with modest increases msly
ovr the Nrn most quarter of the FA, given that the cnvctv
nature of shwrs and any tstms is weakening once they cross the
border from ern QB. Also, we kept thunder isold thru the morn
based on HRRR model runs, which does not show sig cnvctn re-
firing until at least midday. Subsequently, we updated the Rec
and Fire Wx fcsts to reflect lesser ltng activity until Tue
aftn.
Lastly, minor adjustments to fcst hrly temps/dwpts were made
into the late ngt hrs based on late eve obsvd trends with eve
temps again warmer across the N this eve similar to ystdy eve
due to remnant breeze in addition to greater cld cvr. No chgs
to fcst ovrngt lows attm thinking that temps could cool down
more quickly later tngt with rn cooled air.
Orgnl Disc: A warm southwest flow of air will continue across
the region overnight in advance of an approaching cold front
from Quebec. Expect increasing clouds this evening across
northern and central areas tonight and mainly clear skies
Downeast. There could be a shower or isolated thunderstorm
across the far north tonight in advance of the approaching
front. Lows tonight will only fall into the upper 50s to lower
60s.
The front will cross northern areas Tuesday morning and then
cross central and Downeast areas during Tuesday afternoon. The
front will be accompanied by scattered showers and thunderstorms
as it crosses the region. Have decided to include mention of
gusty winds in any thunderstorms Tuesday afternoon from the
Katahdin region on southward to interior Downeast. SB CAPE
forecast in this region is running from about 1000-1500J with
0-6 km shear values 35 to 40 kts. H7-H5 lapse rates are expected
to range from around 6.5-7.0 c/km. Limiting factor may be mid
level dry layer. However, considering the rather strong wind
field aloft, any storms that are able to pop could transport
some gusty winds to the surface. Expect showers and
thunderstorms to wind down by late afternoon as the front
approaches the Downeast coast. High temperatures on Tuesday are
expected to range from the mid to upper 70s across the north
and low to mid 80s Downeast. It will be a bit cooler along the
immediate coast.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A cold front will exit the Downeast coast Tuesday evening then
move across the Gulf of Maine overnight while high pressure
builds toward the region. Will still have a chance of
showers/thunderstorms Downeast early Tuesday night with the
exiting front, with skies then remaining partly cloudy. Mostly
clear skies are expected across northern areas Tuesday night
with building high pressure. High pressure will then cross the
region Wednesday into Thursday with mostly clear/partly cloudy
skies. The exiting cold front along with an upper level trof are
expected to help keep a tropical system east of the region
Wednesday night into Thursday. However, swells from the system
will produce building seas and high surf later Wednesday night
into Thursday along the Downeast coast. Temperatures will be at
near normal, to slightly above normal, levels
Wednesday/Thursday.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
High pressure will remain across the region Thursday night into
early Friday, with a warm front crossing the region later
Friday. Mostly clear skies are expected Thursday night into
early Friday, with increasing clouds later Friday along with a
slight chance of showers late. A weakening cold front will
begin to cross the region Saturday with a chance of
showers/thunderstorms. The remnants of the front could help
support a chance of showers/thunderstorms Sunday. High pressure
is expected Monday. Temperatures are expected to be at slightly
above normal levels Friday through Monday.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: Smoke from forest fires to our west in Canada was
drifting across northern Maine late this afternoon. The smoke
was reducing the surface visibility to 2SM at KCAR at this
hour. Outside of any local visibility restrictions in smoke at
the northern terminals (KFVE/KCAR/KPQI)this evening, we are
generally expecting VFR through tonight. There is the potential
for some patchy fog developing KBGR/KBHB after 08z tonight with
possible IFR developing.
A cold front will cross the region from northwest to southeast.
The front will cross the northern terminals Tuesday morning and
then KBGR/KBHB Tuesday afternoon. The front will be accompanied
by scattered showers and thunderstorms. One or two of the storms
may contain gusty winds. The terminals with the greatest threat
for a gusty thunderstorm are KHUL and KBGR, with brief sub VFR
conditions possible in any heavier thunderstorms.
SHORT TERM: Variable conditions are expected with any
showers/thunderstorms Downeast early Tuesday night. Otherwise,
generally VFR conditions are expected Tuesday night through
Friday. Variable conditions are then expected with
showers/thunderstorms Saturday.
&&
.MARINE...
NEAR TERM: Winds/seas are expected to generally remain below
small craft advisory levels through Tuesday. However, seas could
approach 5 ft at times in the southwest flow late tonight into
early Tuesday.
SHORT TERM: Winds are expected to remain below small craft
advisory levels Tuesday night through Thursday. Seas are
expected to be below small craft advisory levels Tuesday
night/Wednesday. Swell from the tropical system tracking east
of the Gulf of Maine will produce small craft advisory level
seas later Wednesday night into Thursday. Visibilities will be
reduced in showers/thunderstorms and fog early Tuesday night.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...VJN
Short Term...Norcross
Long Term...Norcross
Aviation...VJN/Norcross
Marine...VJN/Norcross
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
721 PM CDT Mon Jul 9 2018
.EVENING UPDATE...
Precip coverage has declined substantially over the last several
hours. RAP mesoanalysis indicates increasing CIN and decreasing CAPE
over the region with weak low level lapse rates, likely due to the
worked over environment due to outflow. While hi-res models have
performed quite poorly today, they all continue the decreasing trend
leaving the CWA mostly dry through the overnight period.
Thus, have decreased PoP/QPF over the next 6 hours and adjusted
hourly temps to account for latest trends.
&&
.PREV DISCUSSION... /ISSUED 635 PM CDT Mon Jul 9 2018/
UPDATE...
00Z Aviation forecast below.
AVIATION...
Outflow boundary at 23Z was located just north of VCT to near PEZ
and to between DRT and 5T9. Isolated SHRAs and TSTMs will continue
through sunset near and south of this boundary. North of the boundary
-RA is ongoing just east of AUS and may temporarily approach the
terminal before dissipating around sunset. VFR conditions will
prevail at TAF sites through the remainder of the evening and through
a portion of the overnight. MVFR ceilings with stratus is expected
to develop after 09Z along the escarpment and impact SAT/SSF/AUS.
Can`t rule out some pockets of IFR ceilings in some spots. Also, some
patchy BR could result in isolated pockets of IFR-MVFR visibilities,
especially where more rain has occurred in the past few days. After
15Z VFR conditions will once again develop.
PREV DISCUSSION... /ISSUED 236 PM CDT Mon Jul 9 2018/
SHORT TERM (Tonight through Tuesday Night)...
Showers and thunderstorms continued across South Central Texas this
afternoon due to heating of a moist uncapped airmass enhanced by a
mid level shear axis. This activity will gradually wind down with
sunset and loss of heating this evening, though may linger across the
northwestern Hill Country to Edwards Plateau overnight in proximity
to shear axis as it drifts north. This shear axis moves away from our
area while the Subtropical Ridge begins to build back over our area
on Tuesday. Proximity to the shear axis will continue low chances of
showers and thunderstorms across our Central Texas and Hill Country
counties on Tuesday, while the seabreeze brings slight chances of
showers and thunderstorms near the Coastal Plains.
LONG TERM (Wednesday through Monday)...
The Subtropical ridge is the dominant feature for our weather in the
long term. Wednesday will be similar to Tuesday with proximity to the
shear axis maintaining slight chances of showers and thunderstorms
over our Central Texas counties and the seabreeze maintaining slight
chances of showers and thunderstorms near the Coastal Plains. A drier
airmass confines slight chances of showers and thunderstorms to
near the Coastal Plains to along Highway 77 due to the seabreeze on
Thursday and Friday. A warming trend of the daytime temperatures is
expected as the airmass and soils dry.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 74 94 75 96 75 / 20 20 - 10 -
Austin Bergstrom Intl Airport 73 94 73 95 74 / 30 20 - 10 -
New Braunfels Muni Airport 73 94 73 95 74 / 20 10 - 10 -
Burnet Muni Airport 71 92 73 94 74 / 20 20 - 20 -
Del Rio Intl Airport 74 95 76 98 76 / 30 10 - - 0
Georgetown Muni Airport 73 93 74 94 74 / 20 20 10 20 -
Hondo Muni Airport 72 94 73 97 73 / 10 10 - - -
San Marcos Muni Airport 73 94 73 95 74 / 30 10 - 10 -
La Grange - Fayette Regional 74 93 74 94 75 / 30 20 - 20 -
San Antonio Intl Airport 74 94 75 95 75 / 10 10 - 10 -
Stinson Muni Airport 74 94 75 97 75 / 10 10 - 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Runyen
Synoptic/Grids...TB3
Public Service/Data Collection...33
Area Forecast Discussion
National Weather Service Grand Forks ND
950 PM CDT Mon Jul 9 2018
.UPDATE...
Issued at 950 PM CDT Mon Jul 9 2018
A few showers skimming the northern parts of Towner and Cavalier
counties, but CAMs models are in pretty good agreement on this
being just an appetizer before the main course later tonight.
Severe storms entering northwestern ND have been handled decently
by the HRRR, and that model has the activity weakening as it moves
east and well before reaching our CWA. This would fit with the
limited instability over our area. The HRRR as well as many of the
other high res models break out some more widespread showers and
storms in the 10-11Z time frame during the early morning hours
with the weak shortwave currently in MT coming over the top of the
ridge. There will be some MUCAPE, particularly in the west, but
think overall the convective activity later tonight and tomorrow
morning will be sub-severe. Did bump up POPs and QPF for current
CAMs trends at least in the western half of the CWA. The precip
will weaken and dissipate as it moves east through MN by mid-day.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 242 PM CDT Mon Jul 9 2018
This afternoon: Showers and a few embedded thunderstorms have moved
into parts of southeast ND as weak embedded wave within mid level
west-northwest flow over ND. Instability is limited and forcing is
disorganized over our CWA, so activity has struggled to maintain
coverage. Weakening trend generally matches current short range
guidance, and should dissipate by fore this evening over southeast
ND and west central ND.
Tonight-Tuesday: Another shortwave moves along the International
Border tonight and exits our CWA by Tuesday afternoon. A warm front
starts to lift northward during the day and destabilization takes
place behind this front. Shower/thunderstorms may begin to increase
in coverage late tonight with the shortwave trough, but intensity
should remain sub severe. A few moderate or even heavy pockets of
precipitation may occur as deep moisture remains in place over the
region (expected PWATs in excess of 1.5 tonight). Increase in
instability occurs as activity is winding down Tuesday and
subsidence is building back over our CWA. CAMs match these
trends (though differ in evolution) and generally show activity
spreading from Central ND into eastern ND after 1 AM and then
moving into MN by midday before dissipating. Adjustments were made
to expand coverage/mention.
Regarding temperatures: Temperatures should remain within seasonal
ranges with lows in upper 50s to mid 60s and highs in the 80s. WAA
in the afternoon does raise possibility highs could be a touch
higher than consensus indicates Tue, but this could be offset by
lingering showers/cloud cover.
.LONG TERM...(Tuesday night through Monday)
Issued at 242 PM CDT Mon Jul 9 2018
Surface high pressure over the Great Lakes will retreat allowing
return flow and increased moisture to set up over the region ahead
of another low pressure system. Some showers and an occasional storm
can be expected in the early morning hours on Wednesday as the warm
front lifts northward.
For Wednesday night into early Thursday...a frontal system is
forecast to cross the area with warmer temperatures and abundant
moisture setting up ahead of it. Thunderstorm development is
expected ahead of the cold front with increased instability in the
warm sector. Limited shear is expected and the greatest threat for
any severe weather will be winds and hail.
Behind the front later on Thursday and Friday...expect slightly
cooler temperatures and a bit drier air as 850mb dewpoints drop.
Tranquil conditions are expected to last into early Saturday until
the next system begins to cross the region...bringing another round
of storms. Otherwise...the end of the period will be cooler with
some lingering showers.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 703 PM CDT Mon Jul 9 2018
Conditions are VFR and will remain so throughout the period with
mainly mid and high clouds moving in. Some showers and possible
thunderstorms moving in after 06Z, although coverage and strength
are still a bit uncertain. Will include a VCSH for now at the
western three TAF sites and if CAMs trend stronger will include
thunder mention a bit later. Light and variable winds will begin
to pick up out of the southeast, with some gusts near 20 kts by
tomorrow afternoon possible.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...JR
SHORT TERM...DJR
LONG TERM...Hopkins
AVIATION...JR
Area Forecast Discussion
National Weather Service Flagstaff AZ
834 PM MST Mon Jul 9 2018
.SYNOPSIS...The monsoon weather pattern will persist over the
region this week, with daily rounds of afternoon and evening
thunderstorms.
&&
.UPDATE...At 8:30pm MST, A line of showers and thunderstorms
extended along a line from Bagdad to Seligman, into Grand Canyon
Village through Kaibito. This line of convection will continue to
move west tonight with clearing skies forecast for the most part
over northern Arizona. As a result, lowered PoPS considerably over
areas east of the current line of convection through midnight.
The latest HRRR and the UofA WRF hint at some thunderstorm
activity developing over southeastern Arizona, and rotating into
the White Mountains into the Payson area after midnight. Given
the latest hi-res data, went ahead and kept scattered
thunderstorms in for the White Mountains into Payson area after
midnight. Otherwise, mainly dry conditions are forecast for Navajo
Nation and Hopi, as well as the Flagstaff and Prescott areas
after midnight.
The remaining forecast elements are in good shape. The updated
gridded and text products have been sent.
&&
.PREV DISCUSSION /334 PM MST/...Expect to see shower and
thunderstorm activity continue through midnight with the largest
concentration of activity near western Coconino and Yavapai
counties. Hi-res models are hinting at the development of an MCS
by late afternoon that propagates into Yavapai County through the
early evening hours bringing a round of moderate to heavy
rainfall. Isolated chances for showers and thunderstorms remain
through the evening elsewhere. Expect coverage for Tuesday to be
mostly along the higher terrain features of the Mogollon Rim and
White Mountains with isolated coverage elsewhere. Main threats
remain to be small hail, gusty winds, and heavy rainfall.
Long range models do not indicate much of a break over the long
term in afternoon shower and thunderstorm activity keeping
moisture locked in over northern Arizona. By Wednesday, the flow
over northern Arizona shifts to become more southerly as the
trough influencing our weather today shifts out. This will open
the door for more widespread activity and increased moisture
across the area. This will likely shift our threats each day more
toward a flash flooding concern. Scattered to numerous storms are
expected each afternoon through the rest of the week.
&&
.AVIATION...For the 06z package...A line of showers and
thunderstorms will continue to move west into Mohave County
tonight. VFR conditions will prevail over northern Arizona
terminal aerodromes tonight, with another round of scattered
thunderstorms forecast to develop along the Mogollon Rim between
18z-24z Tuesday. Aviation discussion not updated for TAF
amendments.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...TM/ET
AVIATION...TM/ET
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Houston/Galveston TX
955 PM CDT Mon Jul 9 2018
.UPDATE...
Rain has ended for Southeast Texas this evening with GOES-16 Total
Precipitable Water satellite imagery showing somewhat drier air
(1.7 inch PWATs this evening versus over 2 inches during the day)
likely keeping rain at bay tonight. Speed convergence may be able
to eke out a shower or two along the coast but this appears to be
so light confidence is not high enough to warrant more than 20
PoPs with this update. Skies have generally cleared south of
Interstate 10 this evening and this may result in at least some
patchy fog development with continued thinning and/or clearing
expected overnight. However, the drier air moving inland may
delay or limit fog development and have not added mention of this
in the forecast for now but trends will need to be monitored for
possible inclusion. Otherwise, remainder of forecast on track with
lows in the 70s inland to low 80s along the coast.
Huffman
&&
.PREV DISCUSSION... /ISSUED 611 PM CDT Mon Jul 9 2018/
AVIATION...
Convection is waning but a small cell near KHOU has produced an
outflow that will shift winds to the east for an hour or so. Skies
should clear tonight and have some concerns that with wet ground
and clearing skies, that there will be some potential for fog by
morning. HRRR and GFS look dry but the NAM is showing some
potential. Will watch trends but current thinking is that some
MVFR fog will be possible prior to sunrise at the northern TAF
sites. Convective temps look several degrees warmer than today so
pushed back the start time for afternoon storms. Moisture looks
less so coverage will be considerably less than what occurred
today. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 74 93 75 93 75 / 20 20 20 30 10
Houston (IAH) 75 92 76 93 76 / 10 40 10 30 10
Galveston (GLS) 80 89 80 89 81 / 20 30 20 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...14
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
647 PM CDT Mon Jul 9 2018
.SHORT TERM...
209 PM CDT
Through Tuesday...
Only a few minor forecast challenges associated with a cold front
that is expected to push through the area overnight into Tuesday.
For the rest of today, fair and warm conditions persist with west
to southwest flow prevailing ahead of the front. A lake breeze
has formed this afternoon, though has made very minimal inland
progress thus far. Temperatures immediately near the lake are
close to 10 degrees cooler than areas a couple miles inland. HRRR
is most aggressive bringing the lake breeze about 5 miles inland
today before retreating again late this afternoon. Not terribly
confident in it getting this far inland given the opposing
boundary layer flow around 10 kt and sporadic mid-teen gusts
showing up in area obs, but something to keep an eye on that will
impact hourly temp trends through the rest of today.
Meanwhile this afternoon, a cold front is draped across Wisconsin
from just north of Green Bay southwest to La Crosse. Spotty
showers and thunderstorms are possible near the front later today
well to our north, but any activity should wane overnight as the
front finally reaches Illinois. The front is expected to cross the
IL/WI state line after midnight tonight and settle south of I-80
mid Tuesday morning. Winds will veer to the northeast behind the
front with a bit of a surge off of Lake Michigan that will keep
temperatures in the 70s near the lake Tuesday. Farther inland
expect temperatures to top out in the mid 80s. Widely scattered
showers and thunderstorms will be possible near the front Tuesday
afternoon south of the Kankakee River Valley. Guidance suggests
moderately strong instability will develop near the front where
dew points are expected to pool into the mid 70s. Steep low level
lapse rates may support a limited wind threat with any of the
stronger storms, but modest flow aloft will limit a more organized
severe threat across our southern counties Tuesday afternoon.
Deubelbeiss
&&
.LONG TERM...
320 PM CDT
Tuesday night through Monday...
1020 mb high pressure over the region to start the period will
provide near seasonable temperatures (highs in mid to possibly a
few upper 80s) and fairly comfortable humidity levels on Tuesday
night into Wednesday. A lake breeze will keeps temps lakeside and
just inland in the upper 70s to around 80.
Thereafter, we`ll return to the persistent above normal
temperature regime as strong mid and upper ridging (low-mid 590s
DM 500 mb heights over local region) takes hold. The pattern
doesn`t look overly active with plenty of dry hours, though
occasional bouts of convection over parts of area will be possible
Friday through Monday as capping does not appear it will be too
strong, and possibility of generation of subtle convectively
induced vorticity maxima to aid in forcing/lift at times.
The surface high will be losing its grip on Thursday, though flow
aloft should be weak enough along with strong land lake temp
differential to support an east-southeasterly lake breeze hugging
the IL shore before possibly getting shunted back east later in
the day. Highs will be primarily in the upper 80s inland and low-
mid 80s IL shore. A weak surface trough to our north with cold
front washing out Thursday night should yield a dry overnight. Low
PoPs north of I-80 on Friday appear reasonable in closer proximity
to the surface trough.
Details on Saturday are much less clear, with possibility of
scattered convection being around to start the day a wildcard
regarding trends the rest of the day and temperatures. Sunday may
have a minima in convective activity, if any, followed by perhaps
a better chance next Monday as a cold front approaches. Any of
the days Friday through Monday certainly have potential to feature
more widespread 90+ degree readings than in official forecast
given progged 850 and 925 mb temperatures, pending resolution of
any cloud cover and convection effects (including how widespread
diurnal Cumulus growth is). Dew points will also likely be into
the 70s for all or most of the area. Thus, on days that can
maximize heating potential, can`t rule out at least portions of
CWA approaching heat advisory criteria. Current EHWO grids will
carry areas of Limited Excessive Heat Risk (heat index of 95-104),
with Sunday being most widespread, given overall uncertainty this
far out.
Castro
&&
.AVIATION...
For the 00Z TAFs...
Watching convection well to the north of the terminals over
northern/central Wisconsin. Timing with the frontal arrival
overnight and weak upper forcing this far south, coupled with
not great moisture suggests shower coverage will be limited across
NE IL and NW IN. Window for showers is genearlly 6-7z to about
10-11z, or during the overnight hours.
Expect a rapid turn to NE winds with the front arrival, with a few
hour period of gustiness. Then expect NE winds to settle around 10
kt or maybe a tad higher for ORD/MDW, slightly weaker inland.
KMD
KMD
&&
.MARINE...
342 PM CDT
A trough/cold front will track southward across the lake through
tonight, flipping winds to northerly behind the front. Top speeds
should generally be up to 20 kt, but can`t rule out a few higher
gusts late tonight. The northerly winds up to 20 kt will focus
into the central and southern portion of the lake on Tuesday, with
the north turning light and variable as high pressure moves
overhead. Current trends suggest that northerly speeds on the
south will not be quite high enough to cause hazardous waves for
small craft in the nearshore waters, though it could be close.
The high pressure will be over the lake on Wednesday, resulting
in light and variable winds of 10 kt or less driven by lake breeze
influences close to shore. The high pressure will slide east on
Thursday as a surface trough approaches, turning winds to brisk
southerly, especially central and northern where a period of
speeds of 25-30 kt looks probable. A weak pressure field will be
over the lake Friday-Saturday, bringing lighter winds and possibly
variable directions.
Castro
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
934 PM EDT Mon Jul 9 2018
.SYNOPSIS...
A cold front will move southeastward across the eastern Great
Lakes and Pennsylvania tonight into Tuesday, then cross the
Mid-Atlantic Tuesday night into early Wednesday. High pressure
will follow for the second half of the week.
&&
.NEAR TERM /THROUGH TUESDAY/...
Dry and clear to mostly clear conditions are expected overnight
as high pressure weakens and drifts offshore. Meanwhile, an
upper level trough and attendant surface cold front will begin
digging southeastward across the eastern Great Lakes. Other than
some high cirrus ahead of the trough or perhaps a few cumulus
due to a slight uptick in low level RH, tonight should be mainly
clear. Patchy fog is possible again in sheltered river valleys.
Went below most guidance for lows given light to calm winds and
a mainly clear sky, which yields lows in the 50s for most areas
(except 65-70 in the urban areas).
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Most of Tuesday will be dry. The aforementioned cold front will
approach the region very late in the day. Before then, despite
temperatures in the lower 90s and dew points in the upper 60s to
near 70, the atmosphere should remain capped around 850 mb. The
cap will erode in the evening hours, but by then we are losing
surface heating and low-level convergence is less than ideal
(unless a surface lee side pressure trough can develop a little
stronger than currently forecast). Still, the presence of
substantial height falls and modest CAPE/shear should force a
few isolated to widely scattered thunderstorms during the early
evening hours, with a gusty thunderstorm not out of the
question. Convection is most likely near the Pennsylvania border
closest to the best forcing/lift from the approaching trough.
Any showers should become very sparse or fall apart altogether
by around or shortly after midnight. Latest guidance (09Z
SREF/12Z NAM and even to an extent the 12Z GFS) have slowed down
the surface front somewhat. A rather potent shortwave at 500 hPa
will rotate around the base of the parent upper trough Wednesday
afternoon, and if the surface front hasn`t cleared central
Virginia by then, a couple thunderstorms (some gusty) would be
possible. For now have kept PoPs at slight chance/isolated.
Northerly flow will advect in drier air Wednesday into Wednesday
night, though dew points aren`t expected to drop as low as they
were this past weekend (50s to lower 60s sfc DPs are forecast as
opposed to 40s and 50s). Temperatures will be near normal.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Model guidance is suggesting that an upper-level trough will be
located either overhead, or just to our east during the day on
Thursday. The trough is a fairly complex feature, with multiple
shortwaves rotating around and digging through the trough axis. Most
model solutions keep us dry during the day on Thursday. However, the
00z Euro and some of the 00z EPS members produce showers and
thunderstorms over the area Thursday afternoon in association with a
shortwave moving through in north-northwesterly flow.
The upper-level trough will move offshore by Friday, allowing a
ridge of high pressure to move in at the surface. This should keep
conditions dry, with high temperatures in the mid-upper 80s.
By the weekend, an extensive ridge at 500 hPa is forecast to become
established over the Central Mississippi Valley. That will lead to
northwesterly flow aloft. Details are unclear this far out, but it
appears as though afternoon showers and thunderstorm are at least a
possibility, as mid-level shortwaves rotate around the periphery of
the ridge. Temperatures and dewpoints will also increase, with highs
in the low 90s and dewpoints in the upper 60s to low 70s by Sunday.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Mainly VFR through Wed night. High pressure weakens and shifts
offshore tonight, then a cold front dropping south out of PA
crosses Tue night into early Wed. Patchy fog possible INVOF
CHO/MRB but not enough confidence in coverage to be included in
the TAF. An isolated thunderstorm could affect northern
terminals (MRB to MTN) Tue eve, but low confidence/coverage.
Light and variable flow is expected over the terminals through
tonight. Light NW flow expected Tue (outside of river/bay
breezes), could briefly go SW in lee of Blue Ridge if lee side
pressure trough develops Tue aft, but should remain AOB 10 kts.
Winds then shift N behind a cold front Tue night, and increase
to around 10 kts with a couple gusts of 15-20 kts possible Wed.
Perhaps an iso thunder chance near CHO Wed eve if the front
doesn`t clear.
A few showers and thunderstorms can`t be ruled out on Thursday, and
then again on Saturday and Sunday. Otherwise, conditions are
expected to remain VFR through the long term period.
&&
.MARINE...
Light winds expected through Tuesday evening. HRRR has a slight
uptick in winds over the middle MD portion of the Bay overnight,
but should stay below SCA thresholds. An isolated thunderstorm
is possible ahead of a cold front Tuesday evening, most likely
near Baltimore. Winds increase a bit out of the north behind the
front late Tuesday night into Wednesday, with marginal SCA
possible. Winds diminish Wednesday night as the front pulls away
and high pressure builds overhead.
Winds are expected to remain below the SCA threshold Thursday
through Sunday. A shower or thunderstorm may be possible on Thursday
and then again on Saturday and Sunday.
&&
.TIDES/COASTAL FLOODING...
Water levels will remain elevated with near minor tidal flooding
possible at times until a cold front turns winds northerly
Tuesday night.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.
&&
$$
SYNOPSIS...DHOF
NEAR TERM...IMR/DHOF
SHORT TERM...DHOF
LONG TERM...KJP
AVIATION...IMR/DHOF/KJP
MARINE...DHOF/KJP
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service San Angelo TX
607 PM CDT Mon Jul 9 2018
.AVIATION...
/00Z TAFS/
Scattered showers and thunderstorms will slowly diminish this
evening, with most of the activity dissipating by 03z. Brief heavy
rainfall and dangerous lightning will be possible with the
stronger storms. Although patchy stratus is possible Tuesday
morning, extensive mid and upper level cloud cover should preclude
development for most locations. For now, have kept ceilings VFR
at all sites, but will need to continue to monitor through the
overnight hours. Light and variable winds overnight will become
south at 5 to 10 knots by mid morning Tuesday.
&&
.PREV DISCUSSION... /issued 250 PM CDT Mon Jul 9 2018/
SHORT TERM...
(Tonight and Tuesday)
Scattered showers and thunderstorms have developed once again
across West Central Texas this afternoon...with precipitable water
values in the 1.7-2.0 inch range and SB CAPE values of around
1000 J/KG. The primary hazards with this activity continues to be
locally heavy rainfall and cloud to ground lightning. Hi res model
guidance including the HRRR and the Texas Tech WRF dissipate most
of this activity after 01-02Z with a few isolated showers
lingering during the overnight hours. Otherwise, temperatures are
holding in the 80s across most of the area due to the abundant
cloud cover and rain.
Another round of isolated to scattered showers and thunderstorms
is possible on Tuesday...as another weak shortwave traverses the
region in the easterly flow aloft. Locally heavy rainfall will
again be the main threat with these storms, with the moisture rich
airmass remaining in place. Otherwise, expect lows tonight in the
lower 70s, with highs tomorrow in the lower 90s.
42
LONG TERM...
(Tuesday night through next Monday)
The generally moist and unstable easterly flow will continue
through the middle of the week, although rain chances will slowly
diminish as we move into the weekend. Tuesday night into Thursday,
a weak easterly wave/shortwave moving west along the southern
side of the anticyclonic flow aloft may provide enough lift at
times for isolated to scattered showers and thunderstorms for
parts of the area. The best chance for convection in our area
appears to be Thursday night for areas mainly north of a Brownwood
to Sterling City line.
Following Thursday night`s rain chances, the upper level ridge
currently anchored to our north is expected to expand back over
our area, reducing rain chances for the area through the weekend.
With the ridge strengthening, the other effect on our area will be
warming temperatures with highs getting back into the upper 90s to
around 100 degrees for most of the area for Friday through early
next week.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 70 90 72 95 / 20 30 10 10
San Angelo 70 93 72 97 / 40 30 5 10
Junction 71 93 73 96 / 30 20 5 10
Brownwood 71 91 72 96 / 30 30 10 10
Sweetwater 71 91 73 95 / 20 30 10 10
Ozona 68 90 71 94 / 40 20 5 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Daniels
Area Forecast Discussion
National Weather Service Tulsa OK
849 PM CDT Mon Jul 9 2018
.DISCUSSION...
The easterly wave continues to slowly move across the area. RAP and HRRR
keep a small area of convection going on the northeast side of the low
overnight. The NAM wants to keep some going in far southeast oklahoma
near the red river where it has another little easterly wave approaching.
Convective trends are about as expected except for those areas. Will keep
some scattered pops overnight in areas north of i-44 and isolated elsewhere
just in case. No other changes with a similar pattern tomorrow.
&&
.PREV DISCUSSION... /Issued 623 PM CDT Mon Jul 9 2018/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Will keep a VCSH remark through 01z at KXNA, otherwise, expect
lingering coverage to remain away from the remaining sites. Also will
tempo light fog in at the AR sites between 09z-13z. Prob groups will
be added for most of the afternoon at the AR sites and KMLC as TSRA
coverage is expected to be similar to this afternoon. Outside of patchy
fog and scattered thunder, VFR TAF elements will prevail at all sites
through the period.
PREV DISCUSSION... /Issued 314 PM CDT Mon Jul 9 2018/
DISCUSSION...
Convective coverage has increased as anticipated this afternoon in
a more moist and less capped atmosphere than what has been
observed for a few days. Water vapor loop shows well-defined vort
max along OK/KS border continuing to drift west and best chance of
storms through the afternoon should remain near and southeast of
the track of this feature. Severe weather threat remains low, but
gusty winds possible along with brief and localized heavy
rainfall. Coverage should become decidedly less with loss of
daytime heating. Similar conditions will be seen Tuesday with
scattered mainly diurnally driven thunderstorms, again with low
threat of wind gusts and heavy rainfall.
The overall trend for the latter part of this week will be for
central U.S. ridge to expand with heights gradually building over
the southern plains. A seasonably moist airmass will remain in
place with thunderstorm chances likely becoming more tied to
terrain influence by the last half of the week. Temperatures will
gradually climb into next week as well, likely necessitating heat
headlines by later this week. There are indications a frontal
boundary will drop into the central plains early next week,
possibly resulting in more veering of low level flow, which would
lower dew points but also bring triple digit heat to some areas.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
LONG TERM....13